Mesoscale Discussion 1886
   NWS Storm Prediction Center Norman OK
   0352 PM CST Tue Dec 29 2020

   Areas affected...Northeast IL...Southeast WI...Far Northwest IN

   Concerning...Heavy snow 

   Valid 292152Z - 300145Z

   SUMMARY...Occasional snow rates of 1+ inch per hour will be likely
   late this afternoon into the evening, as precipitation spreads in
   from the west. A transition to sleet/freezing rain is expected
   across much of this area later tonight.

   DISCUSSION...At 2145Z, snow was increasing across northeast IL and
   spreading into southeast WI, with rates approaching 1 inch per hour
   likely ongoing across the southwest Chicago suburbs, where
   saturation of an initially dry airmass has allowed for precipitation
   to reach the ground. As a large area of precipitation continues to
   spread in from the west, favorable ascent within the dendritic
   growth zone will allow for heavier bands of snow with maximum rates
   exceeding 1 inch per hour through 00Z. Moderate to locally heavy
   precip rates will likely continue into the evening, though continued
   low-level warm advection will result in an eventual changeover to
   sleet or freezing rain later tonight across northeast IL into far
   southeast WI.

   ..Dean.. 12/29/2020

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...IWX...LOT...ILX...MKX...DVN...

   LAT...LON   43078908 43388845 43348785 42488702 41798677 41268676
               40818684 40798804 40958894 41278922 41428891 41558868
               41838853 42498872 43078908